extapi: move authn config keys into api

sync with Base.

Topic: AAA
Bug-Url: https://bugzilla.redhat.com/show_bug.cgi?id=1120720
Change-Id: I5f9104dae94d5992690efbb89b0867ba77926384
Signed-off-by: Alon Bar-Lev <alonbl@redhat.com>